In recent years, there has been increase in commissioned business for carrying out a farm work using a farm work machine owned by an individual or a corporation, with the farm work machine moving from one farm field to another which farm fields are present in geographical distribution. A management center manages farm works which are planned and implemented for many farm fields.
For instance, Patent Document 1 discloses a farm work management system intended to implement a work for each unit farm field in an efficient manner. According to this farm work management system, a farm work machine identifies its own position via reception of radio wave from a GPS satellite and displays a map showing a farm field located in its vicinity, together with an ID number uniquely assigned to this farm field on a monitor screen of an information terminal device. Further, to an electronic controller for controlling the information terminal monitor, there is connected a mobile terminal configured to transmit, via wireless communication, various kinds of information including the farm field ID information related to the farm field in which the farm work machine is located. With this, a host computer disposed in a base station can receive the information from the mobile terminal. After the ID number of the farm field where this farm work machine is located is inputted from the information terminal monitor, if the farm field ID number of the farm field where the farm work machine is located, which ID number is deduced via reception of radio wave from the GPS satellite, is found erroneous, then, the electronic controller can correct the ID number to the correct farm field ID number which has been inputted from the information terminal monitor.
Further, a farm work machine management device configured to divide a farming ground into multiple sectors and to record a work by a farm work vehicle for each sector is known from Patent Document 2. A management terminal unit of this management device includes a communication means operable to establish communication with a controller of a work vehicle, a DVD reader for reading map data from a DVD medium, a GPS receiver and a gyro sensor. With this, the management device retrieves an outer shape of a work field from map data, divides the retrieved work field map data into sectors and records therein local information (presence of an obstacle such as an electric pole, etc.). Moreover, in case the farm work vehicle is a combined harvester, a total discharge amount of rice crops obtained by a harvesting work can be inputted thereto as a harvest amount for the farm field as a whole.
Regarding such an operation as a rice crop discharge from a grain tank or fuel replenishment on a site of farm work by a combined harvester, a technique is known from Patent Document 3 which provides a worker present on the ground with information via a mobile phone so that the worker can cope with such operation as above appropriately. In the known technique, a mobile phone is configured as a displaying means for displaying information generated by the combine harvester. As a grain tank filling amount or fuel remaining amount can be displayed on the mobile phone carried by a worker, even when the worker is alighted from the combine harvester, the worker can grasp a fuel situation of the combine or the filing situation of the grain tank.